Sound conveyer



June 29,1926. 1,590,627

M. W. HIRSHFIELD SOUND CONVEYER Filed Oct. 5, 1922 By @wvfM 4 Patented June 29, 1926.

UNITED STATES MAURICE W. HIRSHFIELD, OF NEW YORK, N. Y.

SOUND CONVEY'ER.

Application filed October 5, 1922. Serial No. 592,539.

This invention relates to sound conveyers or transmitters and more particularly to an arrangement for conveying sound from a source such as the diaphragm of a telephone or phonograph to a sound amplifier, and my invention also includes an arrangement for supporting the amplifier from such source.

here amplifiers have hitherto been applied to a telephone receiver, they have genlu erally been supported by mounting it over the cap at the diaphragm end thereof. I have found, however, that the sound issuing from the diaphragm through the opening in the cap suffered considerable dispersion at its initial introduction into the amplifier, which fact detracted considerably from the volume and quality of sound waves issuing eventually from the amplifier. It is one ob ject of this invention, therefore, to provide means for preventing such dispersion and loss as the waves enter the amplifier.

I have found that by directing the sound waves into the amplifier for a substantial distance, in such a manner that they travel without decreased velocity and even with an increased velocity, the objectionable dispersion is minimized considerably.

I have further found that the character of instrument hitherto employed for supporting an amplifier from the source, genorally set up vibrations in the end wall of the amplifier which destroy to a considerable extent the natural resonance of the sound issuing from the source, with the consequent impairment of the action of the amplifier. Another of the important objects of this invention is therefore, the provision of an arrangement for eliminating such action.

A further object of this invention is the provision of a device as described above which can be readily applied to an ordinary telephone receiver as an attachment thereto, and is inexpensive to manufacture, easy to attach and highly eflicient in operation.

For the purpose of attaining these objects and such other objects as may appear or be pointed out, I have illustrated one embodiment of the invention in the drawings wherein;

Figure l is a front elevation of a telephone receiver cap embodying my invention; and

Figure 2 is a vertical section taken on the line 22 of Figure 1.

Before proceeding to describe the embodimentillustrated in the drawings, I will premise that my invention is preferably to be in the form of an attachment to an instrument such as the telephone receiver, and is so characterized that the amplifier to be used therewith is in turn to be in the form of an attachment thereto.

Referring to the drawings there is shown a cap 10 which may be the cap of an ordinary telephone receiver, or a special cap adapted to be mounted on said receiver in place of the cap heretofore used. Said cap comprises a disc 11 having a rearwardlyextending flange 12 on its periphery forming a cavity to receive one end of the body of the telephone receiver. For this purpose the inner surface 13 of flange 12 is screwthreaded to cooperate with the exterior screw-threader usually found on one end of the body of the telephone receiver. The disc 11 is provided with a centrally-disposed aperture 15 through which sound is normally transmitted from the diaphragm with in the body of the receiver adjacent disc 11.

The cap as above described may be the usual telephone receiver cap. To prevent possibility of difiusion and loss of sound this invention provides means for preventing leakage and diffusion of sound from opening 15 to the amplifiers. For this purpose there is provided a short tube 16 preferably of metal, having the reduced portion 17 arranged to be received snugly in the opening 15, the reduced portion 17 forming a shoulder 18, which forms an end stop and also a snug joint with the end face of disc 11. The amplifier is adapted to fit snugly over tube 16 (as by means of the central tube 13 in the patent to Cobb, No. 906,388, see Fig. 4). It will there be seen that I have provided a construction which is extremely inexpensive, and which can be attached and detached quickly and at will, to and from any standard telephone receiver and to which an amplifier can be quickly detached and attached.

A ring 20, of sound-deadening material such as rubber, fitting over thetube 16 as shown in the drawings aids in forming a leak-proof joint between the tube, disc and am lifier.

ounds from the diaphragm are thus led through tube 16 into the amplifier without possibility of leakage, since the joints are leak-proof, and without possibility of diffusion before r aching th amplifie since the sound Waves are constrained to travel with in the confines of tube 16 which directs said Waves into the amplifier. As this tube extends into the amplifier for a substantial distance, the action of this is not only to minimize the ditiusion of the sound "craves earlier than desired, but will cause these Waves to be directed With undinii n-ished ye locity in the direction of the longitudinal axis of the amplifier.

Having thus described my invention and illustrated its use, What I desire to claim and to secure by Letters Patent is:

For use with a sound-producing mecha- MAURICE W. I-IIRSHFIELD. 

